1. Field of the Invention
This invention relates to electrode coating and particularly to a new and improved coating for graphite electrodes which reduces high temperature oxidation of the electrodes.
A satisfactory oxidation resistant coating for graphite electrodes should meet the following criteria: oxidation resistance; adherence; low volatility; low permeability and porosity; thermal compatibility; low diffusion rate of oxygen and carbon; resistance to spalling and erosion; chemical compatibility with furnance environment; ease of repair; and low cost.
2. Description of the Prior Art
One primary method of manufacturing steel involves melting the components of the steel using electric current applied by large graphite electrodes. The residual porosity of graphite electrodes makes them susceptible to oxidation at high temperatures. Because of such oxidation, the electrodes become progressively unusable and must be replaced. Such replacement is undesireable not only because of the cost of the replacement electrodes but also because of reduced production capacity during resultant "down time".
Previous methods to reduce high temperature oxidation of graphite electrodes have involved plasma spraying of the electrodes with materials such as titanium and zirconium, prior to heating the electrodes to very high temperatures. Such methods, however, are relatively difficult and expensive.
In view of the above mentioned problems, therefore, it is an object of the present invention to provide a simple and economical process for protecting graphite electrodes from oxidation.